Often criticized for her weight, Kelly Clarkson has debuted a slimmed-down figure Sunday night at the Billboard Music Awards.

Wearing a pink gown with a plunging neckline, Clarkson took the stage to perform her new single "Dark Side." The "American Idol" winner received frenzied applause for the number.

The singer's fluctuating weight has been speculated in the media since her days on "American Idol" in 2002. Within minutes of her performance at the Billboard Awards, fans took to online resources such as Twitter posting about Clarkson's trim figure as well as her voice at the event.

Just two months ago, reports revealed that Clarkson was romantically involved with Brandon Blackstock- the son of her manager Narvel Blackstock, and the stepson of Reba McEntire.

"Before Brandon, Kelly had a really tough time with love," said a source close to the 30-year-old, according to Us Weekly. "[Brandon] is just what she needed."

The "A Moment Like This" singer has a very busy schedule ahead with NBC's new television series "Duets" kicking off this week. The show sees Clarkson alongside John Legend, Robin Thicke, and Lionel Richie, among others.